There has been a great deal of progress in autism research since Infectious Behavior was published. As described on the book’s blog (which is updated every week or two: infectiousbehavior.wordpress.com), these advances include increased knowledge about environmental risk factors, including maternal infection during pregnancy and various toxins. Many parents have put their autistic children on special diets to avoid certain foods, and recent work highlights the differences in the types of bacteria in the gastrointestinal tract of autistic versus neurotypical kids. In fact, manipulation of the gut microbiome has become a very hot topic in the last year, with several publications showing that this can have profound effects on behavior in mouse models. There have also been important studies on novel therapeutic avenues, such as manipulation of the immune system in animal models of autism. Moreover, some therapies that proved effective in mouse models of related disorders such as Fragile X syndrome have advanced to human clinical trials. There are also new clinical trials beginning to test the effects of fever, purines, and altering the gut ecosystem in autism.